Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
The formation of ice on the wind turbine blades adversely affects performance of the wind turbine. At times, icing can be so severe that it prevents the wind turbines from producing power even at ideal wind conditions. In addition, icing produces imbalances in the blades and rotor, which can generate excessive vibrations and stresses in the powertrain components.
Various proposals have been made for deicing wind turbine blades. Reference is made, for example, to U.S. Pat. No. 6,890,152, which suggests to use vibrators configured in the turbine blades to vibrate the blade and cause the ice to break off. The vibrators may be acoustic wage generators, such as sonic horns. U.S. Pat. Appln. Pub. No. 2010/0189560 suggests deicing wind turbine blades by a controlled acceleration and subsequent deceleration of the blades. U.S. Pat. Appln. Pub. No. 2010/0189560 suggests using a pitch angle controller to individually induce rotational vibrations in the respective blades within a predetermined azimuth angle range of the blade.
Accordingly, the industry is continuously seeking new and efficient methods to device wind turbine blades.